A molded structure for use in such a conventional droplet discharging apparatus is known as disclosed in Patent Citation 1.
Patent Citation 1: WO02/002697.
As depicted in the citation, a nozzle chamber plate has a recess provided therein which acts as a group of separate ink chambers communicated with a nozzle, a group of separate. ink flow passages, and a common ink flow passage and bonded at the upper side with an oscillator plate. This type of structure is advantageous that the components about the nozzle are simplified. The two plates are bonded to each other by an adhesive or namely varnish as described in the citation. However, the bonding of the plates using such an adhesive. may flow into and block the flow passage.
It is assumed, as shown in FIG. 11A, that the nozzle chamber plate has a recess 42x′ acting as a pressure chamber 42′ equal to the separate ink chamber and a groove 35x′ acting as a flow passage 35′ of a square shape in the cross section. In the drawing, the recess and the groove in the nozzle chamber plate are expressed by the outlines. It is also noted that the nozzle chamber plate is joined by bonding to a diaphragm plate.
When the adhesive is applied to the upper side of the plate, it may stagnate in the upper corners CT due to its surface tension. When the two plate are joined to each other, the adhesive stagnating in the upper corners CT will run into the flow passage by contacting the other plate, thus choking the flow passage. The adhesive running into the flow passage may also stagnate in the lower corners CD, thus resulting possibly in the choking of the flow passage. In this case, as the lower corners CD are located close to the upper corners CT, their combination may encourage the choking of the flow passage and will hence decline the yield of the production.
For overcoming the choking of the flow passage at the corners with the adhesive, a modification may be made in which a tapered region 35e′ is provided between the flow passage 35′ and the pressure chamber 42′, as shown in FIG. 11B. However, in the modification, the pressure developed in the pressure chamber 42′ for delivering the liquid will be dispersed along the tapered region 35e′, thus lowering the efficiency of dissipation of the pressure. It is also essential for maintaining the resistance to a flow in the flow passage to make another resistance to a flow in the tapered region 35′, whereby the manufacturing process will be troublesome. Moreover, the tapered region 35e′ may cause the construction about the pressure chamber 42′ to be uneven in the rigidity.
Accordingly, it would be desirable to provide a droplet discharging apparatus which is simple in the structure, free from choking of the flow passage, and high in the manufacturing efficiency and a method of manufacturing the droplet discharging apparatus.